A rotary electric machine is used as a drive source of a vehicle in an electric vehicle equipped with a fuel cell or a hybrid vehicle disposed with an engine and a rotary electric machine. The rotary electric machine is connected to a power source such as a fuel cell or a high-voltage electric storage device. The operation control of the rotary electric machine is performed while a state of the power source is monitored.
For example, Patent Document 1 discloses a controller of a fuel cell vehicle having a fuel cell and an electric double layer capacitor, which includes comprehending the upper limit total power that can be output based on the upper limit power generation amount of the fuel cell and the upper limit discharge amount of the capacitor to limit the upper limit of a torque command within the range thereof. As a result, if the fuel cell has an abnormality and the upper limit power generation amount decreases, it is described that the reduction of the upper limit total power is constrained by the discharge power of the capacitor and that the abrupt drop is constrained in the motor output torque based on the torque command.    Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2003-61212